1. Field of the Invention
The present invention relates to an image processing device which processes an image data input from outside and outputs the image data to a hold type display device, and an image display system including the same.
2. Description of the Related Art
In recent years, a low-profile display such as a liquid crystal display (LCD) has been widely spread in substitution for a CRT (cathode ray tube), and a technique for a moving-image display on the LCD has attracted attention.
Unlike an impulse type display device such as the CRT, when displaying the moving image in the hold type display device such as the LCD, a display of all pixels constituting a screen is held during a period from when a certain one in a plurality of frames or fields (hereafter, simply referred to as “frames”) constituting the moving image is specified to be displayed, until when a next frame is specified to be displayed. Thus, in the hold type display device, due to a so-called eye trace integration (afterglow characteristics exhibited in a human retina when tracing the moving image) effect, there are issues that motion blur such as blur of a front edge, trailing of a rear edge, and delay of perception position occurs in a moving object. In particular, in the LCD, it is considered that this motion blur is likely to be generated due to slowness in response speed of the liquid crystal.
To solve such issues, there is an overdrive technique as one of the techniques for suppressing the motion blur by improving response characteristics of the LCD. In the overdrive technique, to improve the response characteristics to a step input in the LCD, for example, to the step input, a voltage higher than a target voltage corresponding to an instructed luminance value is applied in a first frame when the input signal is changed. Thereby, the speed of a luminance transition is accelerated. By utilizing this overdrive technique, the response speed of the liquid crystal increases in a middle gradation region, and it is possible to obtain an effect suppressing the motion blur. Moreover, in the overdrive technique, by changing a wavelength of the voltage applied in accordance with a motion vector in each frame, a technique more efficiently suppressing the motion blur is also proposed (for example, refer to Japanese Unexamined Patent Publication No. 2005-43864).